#box1{
	height: 100px;
	width:  100px;
	background: yellow;
	/*设置左悬浮方式*/
	float: left;
}
#box2{
	height: 100px;
	width:  100px;
	background: green;
	float: left;
	/*设置相对定位属性*/
	position: relative;
	/*设置位置定位*/
	right: 50px;
	left:  50px;
	top:   50px;
	/*设置透明度*/
	opacity: 0.8;
}
#box3{
	height: 100px;
	width:  100px;
	background: blue;
	float: left;
	
}